Air pump



Oct. 31, 1933. B SKU! 1,933,223

AIR PUMP Filed Sept. 21, 1951 INVGN TO K Patented Get. 31, 1933 "owirsostares AIR PUMP Einar Borgvald Skui, Holmen, Norway ApplicationSeptember 21, 1931, Serial No.. 564,191, and in Norway September 24,1930 7 Claims. (Cl. 208-155) The present invention relates toimprovements in air-pumps of the type which are arranged in a frame tubeof cycles or other vehicles provided with pneumatic tires, where thetube in question is closed at one end and servesas a pump barrel inwhich reciprocates a piston rod having a bell-shaped elastic pistontherein, which is provided with internal means, operable to expand thepiston tightly against the inner surface of the.

barrel.

The invention also comprises special arrangements or" the other parts ofthe pump, enabling the same to be adapted in already existing frametubes and in such manner that the pump may be 115 easily mounted, may beadapted for tubes of different lengths and so that the pump is effectivein use. j

The invention is by way of example illustrated in the accompanyingdrawing in which:

? Fig. 1 shows the pump arranged in a frame tube of a bicycle.

Fig. 2 shows a transverse section through the piston and the rod securedthereto.

Fig. 3 shows a spring arrangement for the piston in extended condition.

' Fig. a shows a detail arrangement.

Fig. 5 shows in section the bottom plug of the pump barrel.

Fig. 6 is a side view of a modification of the pump handle.

Fig. 7 is a side view of an arrangment for the mounting.

In the drawing 1 is a frame tube of a bicycle, which tube at its top endis provided with a str ngthening interior 1a. 2 is the seat pin carryinga member 3 to which the seat is secured. A pump piston 4, secured to thelower end of a piston rod 5 is introduced into the tube 1 through theinterior 1a. The piston rod is at its top provided with a handle 6adapted to be adjusted longitudinally in relation to the piston rod.Said handle will be more fully described below. The bottom end of thetube 1 is closed by a plug 7 of elastic material, for instance, rubber,which forms the bottom of the pump barrel formed by the tube 1. As shownin Fig. 5 the plug is at its top provided with a recess 7 the walls ofwhich diverge upwardly, so that the top edgeportions of the plug arerelatively thin. By this arrangemerit the compressed air in the pumpbarrel during the pumping will press the walls of the plug outwardlyagainst the tube and increase the tightening effect as the compressionincreases. A nipple 8 is screwed into the tube 1 for connection with thepump hose, and said nipple opens into the recess 7 so that it retainsthe plug without preventing the piston from being displaced fully downto the plug.

, The bell-shaped piston packing 11 (Fig. 2) is retained between twoplates 9 and 10 on a bolt 12, and pressed against the barrel walls bymeans of a suitable spring device, which latter may consist of springyfingers 13 connected to the disc 10. As shown in Fig. 3 the disc 10 andthe fingers 13 may be integrally formed from a circular piece of springsteel or the like of suitable elasticity, by providing the same with acentral hole for the bolt 12 and cutting away a series of wedge-shapedportions 14 so that the fingers or arms 13 are formed.

If desired the spring action of the fingers 13 may be increased byconnecting their other ends, for instance, by means of bent-overportions 13, to a split spring ring 15 (Fig. 4).

The tube-shaped piston rod 5 is as illustrated in Fig. 2 divided intotwo parts of which the shorter lower part 16 may be telescopicallydisplaced in the upper one, so that the length of the piston rod may beadjusted to fit tubes 1 of different lengths. When the correct length ofthe rod has been adjustedthe two tube parts are secured to each other bymeans of the ar rangement illustrated at the drawing, Fig. 2. The tubepart 16, the lower end of which rests against the disc 9, is at itsupper end slotted and receives a conical nut 17 into which the end ofthe bolt 12 is screwed. By tightening the bolt 12 the slotted end of thetube 16 is expanded and is thereby secured in the tube 5.

The top end of the piston rod 5 is as above mentioned provided with ahandle 6, and in order to obtain a sufliciently long piston stroke afterthe handle has been moved free of the seat pin 2, the handle is arrangedsliclable in relation to the tube 5. For this purpose the handle may behollow and telescopically displaceable on the top end part of the tube5. Said end part is provided preferably with two diametrically opposedpins 18 which extend into slots 19 in the handle 6. At the lower endeach slot 19 is provided with an angularly directed slot 20, into whichthe pins 18 may be caused to pass by turning the handle, and therebylock the handle from displacement longitudinally in relation to the tube5 during the pumping. Instead of the just described arrangement anyother suitable locking device may be used.

The top end of the handle 6 has a threaded opening 20 through which thepump hose 21 may be introduced into the hollow piston rod 5 Fri" whennot in use. The end of the hose may be secured to the handle by means ofa threaded head 21 which engages in the opening 20.

In Fig. 7 is illustrated an arrangement for mounting of the pump, thatis for insertion of the piston with its spring device through theinterior 1a of the tube. The piston 4 is first introduced into a sleeve22 of thin metal plate, the outer diameter of which is sochosen, that itmay be passed down into the interior 1a. At its top the sleeve 22 isprovided with bent over flaps 23 which engages the top of the barrel 1and holds the sleeve 22 from moving into the barrel as the piston ispressed downwardly therein. It is obvious that as soon asthe pis. tonpasses from the sleeve 22 it will expand and the'sleeve can then belifted frorn the barrel.

Having now particularly described and ascer tained the nature of my saidinvention .and in a the bell-shaped piston is secured between two discs,one of which is provided with radial springy fingers. 7 3. An air-pumpaccording to claim 1, in which the bell-shaped piston is secured betweentwo discs, one of which is provided with radial springy fingers, saidfingers being loosely connected to a ring-shaped spring, which increasesthe expansion of the piston.

4. An air-pump according to claim 1, in which the piston rod consists ofinner and outer telescopically connected tubes, the piston beingarranged at the free end of the inner tube and is secured thereto bymeans of a bolt screwed into a conical nut inserted in the other slottedend of said inner tube, so that tightening of the bolt expands theslotted end of the tube and thereby secures the same in the outer tube.

5. An air-pump according to claim 1, in which the piston prior to itsmounting is inserted in a sleeve fitting into the narrowest part of thepump barrel, which sleeve is provided with abutments preventing the samefrom passing into the barrel when the piston is forced thereinto.

6. An air-pump according to claim 1, in which the piston rod is providedwith a handle normal- 1y engaged therewith for adjustment in alongitudinal direction of the piston rod.

'7. An air-pump according to claim 1 in which one end of the frame tubeis closed by an elastic plug which in its top portion has a recess thethickness of the encircling walls of which decrease towards the top, thehose nipple of the pump communicating with said recess through anopening in the plug.

EINAR BORGVALD SKUI.

